1. Field of the Invention
The present invention relates to a semiconductor device tray removing apparatus suitable for use to automatically remove trays stored in a tray storage container for automatically delivering semiconductor devices loaded on the trays to a semiconductor device testing apparatus and to a semiconductor device tray storing apparatus suitable for use to automatically store trays loaded with tested semiconductor devices in the tray storage container.
2. Description of the Related Art
Many semiconductor device testing apparatuses for measuring the electrical characteristics of semiconductor devices to be tested, i.e. devices under test (commonly called DUT), by applying signals of a test signal of a predetermined pattern to the devices, have a semiconductor device handling (transporting and processing) apparatus (commonly called handler) integrally connected thereto for transporting semiconductor devices to a testing or test station where they are brought into electrical contact with sockets of the test head of the testing apparatus, followed by carrying the tested semiconductor devices out of the testing station and sorting them out into conforming (pass) and non-conforming (failure or defective) articles on the basis of the test results.
In the following disclosure the present invention will be described by taking semiconductor integrated circuits (as will be referred to as IC hereinafter) typical of semiconductor devices by example for the convenience of explanation. The term "semiconductor device testing apparatus" (IC testing apparatus) as used herein generally means both the semiconductor device testing apparatus (IC testing apparatus) having no handler connected thereto and the semiconductor device testing apparatus (IC testing apparatus) having a handler connected thereto.
With an increased number of IC terminal pins attendant with an enhanced level of the IC integrity, in the semiconductor device testing apparatus (as will be referred to as IC testing apparatus hereinafter) having incorporated therein a handIer of the gravity-dropping type in which ICs are allowed to slide down a slanted transport path by their own weight to undergo a test, it has been difficult to test ICs with an increased number of terminals because of the difficulty to allow such numerous-pinned ICs to slide naturally. For this reason, in recent years the IC testing apparatus has integrated therewith a handler called "forced horizontal transporting system" capable of picking up ICs with a vacuum pick-up head and transporting the picked up ICs to any desired location by the use of X-Y direction transport means.
Typically, there have been heretofore put in practical use the following two types of the IC testing apparatus having a handler incorporated therein:
(1) The type in which a tray loaded with a number of ICs arranged in a plane is placed at a predetermined position in the IC testing apparatus, followed by a predetermined number of ICs being picked up from the tray by a vacuum pick-up head, the thus picked up ICs being transported by an X-Y direction transport means sequentially to a preheating section and then to a test section where the ICs are subjected to a test, whereafter the tested ICs are sorted out into conforming and non-conforming articles before they are returned to trays by the use of the X-Y direction transport means.
(2) The type in which a number of ICs are loaded in a planar array on a universal tray (customer tray ) (which is designed to be used by the user to transport and store ICs in a desired area outside of the IC testing apparatus) and then the universal tray loaded with the ICs is placed in the loader section of the IC testing apparatus where the ICs are transferred from the universal tray onto a test tray capable of withstanding high and low temperatures, followed by the test tray being transported through a constant temperature chamber to a test section where the ICs as loaded on the test tray are brought into electrical contact with IC sockets of a tester head to undergo a test, upon completion of the test the test tray being conveyed through a temperature stress removing chamber out to an unloader section where the tested ICs are sorted out into conforming and non-conforming articles before they are transferred to universal trays.
The IC testing apparatus having the former type (1) of handler is rather slow in the processing speed and hence requires a relatively long time for testing since the number of ICs which can be tested at a time is limited to two to four. In other words, the IC testing apparatus of the type (1) is not suitable for high speed processing. In contrast, the IC testing apparatus having the latter type (2) of handler permits ICs as loaded on the test tray to be put into electrical contact with IC sockets of the tester head in the test section, so that it is possible to test as many ICs as sixteen, thirty-two or sixty-four, for example, at a time. Therefore, the general trend at present is toward the use of the IC testing apparatus having the latter type (2) of handler.
First, the general construction of the prior art IC testing apparatus having the latter type (2) of handler integrated therewith will be described with reference to FIGS. 6 and 7. The illustrated IC testing apparatus comprises a chamber section 100 for testing ICs such as semiconductor memories which have been brought in as loaded on a test tray TST, an IC storage section 200 for storing ICs to be tested (ICs under test) and ICs already tested and sorted, a loader section 300 where ICs to be tested which a user has beforehand loaded on universal trays (customer trays) KST are transferred and reloaded onto a test tray TST capable of withstanding high/low temperatures, and an unloader section 400 where the tested ICs which have been carried on the test tray TST out of the chamber section 100 subsequently to undergoing a test therein are transferred from the test tray TST to the universal trays KST to be reloaded on the latter. The unloader section 400 is generally configured to sort out tested ICs based on the data of the test results and load them on the corresponding universal trays.
The chamber section 100 comprises a constant temperature or thermostatic chamber 101 for imposing temperature stresses of either a designed high or low temperature on ICs under test loaded on a test tray TST, a test chamber 102 for conducting electrical tests on the ICs under the temperature stress imposed in the constant temperature chamber 101, and a temperature stress removing chamber 103 for removing the temperature stress imposed in the constant temperature chamber 101 from the ICs having undergone the tests in the test chamber 102. The test chamber 102 contains therein the tester or test head 104 of the IC testing apparatus, the test head 104 serving to apply various testing electric signals to the ICs electrically contacted with the IC sockets thereof and to receive response signals from the ICs and transmit same to the IC testing apparatus.
The test tray TST is moved in a circulating manner from and back to the loader section 300 sequentially through the constant temperature chamber 101, the test chamber 102 and the temperature stress removing chamber 103 of the chamber section 100, and the unloader section 400. The constant temperature chamber 101 and the temperature stress removing chamber 103 are taller than the test chamber 102 and have upper portions protruding beyond the top of the latter, as is apparent from FIG. 7. Spanning between these protruding upper portions of the constant temperature and temperature stress removing chambers 101, 103 is a base plate 105 as shown in FIG. 7 on which there is mounted a test tray transporting means 108 by which test trays TST are transported from the temperature stress removing chamber 103 toward the constant temperature chamber 101.
If ICs have had a high temperature applied thereto in the constant temperature chamber 101, the temperature stress removing chamber 103 cools the ICs with forced air down to the room temperature prior to delivering them out to the unloader section 400. If ICs have had a low temperature of, say, about -30.degree. C. applied thereto in the constant temperature chamber 101, they are heated with heated air or a heater up to a temperature at which no condensation occurs prior to delivering them out to the unloader section 400.
A test tray TST, loaded with ICs being tested in the loader section 300, is conveyed from the loader section to the constant temperature chamber 101 of the chamber section 100 which is equipped with a vertical transport means adapted to support a plurality of (say, nine) test trays TST in the form of a stack. In the illustrated example, a test tray newly received from the loader section 300 is supported on the top of the stack. while the lowermost test tray is delivered out to the test chamber 102.
ICs to be tested are loaded with either a predetermined high or low temperature stress as the associated test tray TST is moved sequentially from the top to the bottom of the stack by the vertically downward movement of the vertical transport means and during a waiting period until the test chamber 102 is emptied. In the center of the test chamber 102 there is located the tester head 104. The test tray TST which has been carried one by one out of the constant temperature chamber 101 is placed onto the tester head 104 where a predetermined number of ICs out of the ICs under test loaded on the test tray are brought into electrical contact with IC sockets (not shown) disposed in the tester head 104, as will be discussed hereinbelow. Upon completion of the test on all of the ICs placed on one test tray through the tester head 104, the test tray TST is conveyed to the temperature stress removing chamber 103 where the tested ICs are relieved of heat to be restored to the room temperature prior to being delivered to the unloader section 400.
Like the constant temperature chamber 101 as described above, the temperature stress removing chamber 103 is also equipped with a vertical transport means adapted to support a plurality of (say, nine) test trays TST stacked one on another. In the illustrated example, a test tray newly received from the test chamber 102 is supported at the bottom of the stack while the uppermost test tray is discharged to the unloader section 400. The tested ICs are relieved of heat to be restored to the outside temperature (room temperature) as the associated test tray TST is moved successively from the bottom to the top of the stack by the vertically upward movement of the vertical transport means.
The tested ICs as carried on the test tray TST are passed to the unloader section 400 where they are sorted out by categories based on the data of the test results and transferred onto and stored in the corresponding universal trays KST. The test tray TST emptied in the unloader section 400 is delivered back to the loader section 300 where it is again loaded with ICs to be tested from the universal tray KST to repeat the same steps of operation.
As shown in FIG. 7, the IC transfer means for transferring ICs from the universal tray KST to the test tray TST in the loader section 300 may be in the form of X and Y direction transfer means 304 comprising a pair of opposed parallel rails 301 mounted on the base plate 105 in the loader section 300 and extending in the forward-rearward direction of the IC testing apparatus (referred to as Y direction herein), a movable arm 302 spanning and movably mounted at opposite ends on the pair of rails 301, and a carriage 303 mounted on the movable arm 302 for movement therealong longitudinally of the arm, that is, in the right to left direction of the testing apparatus (referred to as X direction herein). With this construction, the carriage 303 is movable in the Y direction between the universal tray KST and the test tray TST as well as in the X direction along the movable arm 302.
The carriage 303 has a vacuum pick-up head vertically movably mounted on its bottom surface. The movement of the carriage 303 in the X and Y directions and the downward movement of the vacuum pick-up head bring the vacuum pick-up head into abutment with the ICs placed on the universal tray KST to pick them up by vacuum suction for transfer from the universal tray KST to the test tray TST. The carriage 303 may be provided with a plurality of, say, eight vacuum pick-up heads so that eight ICs at a time may be transported from the universal tray KST to the test tray TST.
It is to be noted here that means 305 for correcting the orientation or position of an IC called "preciser" is located between the stop positions for the universal tray KST and test tray TST. The IC position correcting means or preciser 305 includes relatively deep recesses into which ICs as being attracted against the vacuum pick-up heads are released to fall prior to being transferred to the test tray TST. The recesses are each bounded by vertical tapered side walls which prescribe for the positions at which the ICs drop into the recesses by virtue of the tapering. Once eight ICs have been positioned relative to each other by the position correcting means 305, those accurately positioned ICs are again attracted against the vacuum pick-up heads and transferred to the test tray TST. The universal tray KST is provided with recesses for holding ICs which are sized larger as compared to the size of ICs, resulting in wide variations in positions of ICs stored in the universal tray KST. Consequently, if the ICs as such were vacuum picked up by the vacuum pick-up heads and transferred directly to the test tray TST, there might be some of them which could not be successfully deposited into the IC storage recesses m the test tray TST. This is the reason for requiring the position correcting means 305, as described above, which acts to arrange ICs as accurately as the array of the IC storage recesses in the test tray TST.
The unloader section 400 is equipped with two sets of X and Y direction transfer means 404 which are identical in construction to the X and Y direction transfer means 304 provided for the loader section 300. The X and Y direction transfer means 404 perform to transfer the tested ICs from the test tray TST delivered to the unloader section 400 onto the universal tray KST. Each set of the X and Y direction transfer means 404 comprises a pair of opposed parallel rails 401 extending in the forward-rearward direction of the testing apparatus (Y direction), a movable arm 402 spanning and movably mounted at opposite ends on the pair of rails 401, and a carriage 403 mounted on the movable arm 402 for movement therealong longitudinally of the arm, that is, in the right to left direction of the testing apparatus (X direction).
FIG. 8 shows the construction of one example of the test tray TST. The illustrated test tray TST comprises a rectangular frame 112 having a plurality of equally spaced apart parallel cleats 113 between the opposed side frame members 112a and 112b of the frame, each of the cleats 113 having a plurality of equally spaced apart mounting lugs 114 protruding therefrom on both sides thereof and each of the side frame members 112a, 112b opposing the adjacent cleats having similar mounting lugs 114 protruding therefrom. The mounting lugs 114 protruding from the opposed sides of each of the cleats 113 are arranged such that each of the mounting lugs 114 protruding from one side of the cleat 113 is positioned intermediate two adjacent mounting lugs 114 protruding from the opposite side of the cleat. Similarly, each of the mounting lugs 114 protruding from each of the side frame members 112a and 112b is positioned intermediate two adjacent mounting lugs 114 protruding from the opposed cleat. Formed between each pair of opposed cleats 113 and between each of the side frame members 112a and 112b and the opposed cleats are spaces for accommodating a multiplicity of IC carriers 116 in juxtaposition. More specifically, each IC carrier 116 is accommodated in one of an array of rectangular carrier compartments 115 defined in each of aforesaid spaces, each compartment 115 including two staggered, obliquely opposed mounting lugs 114 located at the diagonally opposed corners of the compartment. In the illustrated example wherein each cleat 113 has sixteen mounting lugs 114 on either side thereof, there are sixteen carrier compartments 115 formed in each of aforesaid spaces, in which sixteen IC carriers 116 are mounted. Since there are four of the spaces in the illustrated example, 16.times.4, that is, 64 IC carriers in total can be mounted in one test tray TST. Each of the IC carriers 116 is attached to two of the mounting lugs 114 by fasteners 117.
Each of the IC carriers 116 is of identical shape and size in its outer contour and has an IC pocket 119 formed in the center for accommodating an IC device therein. The shape of the IC pocket 119 of each IC carrier 116 is determined depending on that of the IC device to be accommodated therein. In the illustrated example the IC pocket 119 is in the shape of a generally square recess. The outer dimensions of the IC carrier 116 are sized so as to be loosely fitted in the space defined between the opposed mounting lugs 114 in the carrier compartment 115. The IC carrier 116 has flanges at its opposed ends adapted to rest on the corresponding mounting lugs 114, these flanges being formed therethrough with mounting holes 121 for receiving fasteners 117 therethrough and holes 122 for passing locating pins therethrough.
In order to prevent IC devices from slipping out of place within the IC carrier 116 or jumping out of the carrier, a pair of latches 123 are attached to the IC carrier 116, as shown in FIG. 9. These latches 123 are integrally formed with the body of the carrier so as to extend upwardly from the base of the IC pocket 119, and are normally resiliently biased such that the top end pawls urged toward each other by virtue of the resiliency of the resin material of which the carrier body is made. When the IC is to be deposited into or removed from the IC pocket 119, the top ends of the two latches 123 are expanded away from each other by a latch releasing mechanism 125 disposed on opposite sides of an IC suction 124 for picking up an IC device prior to effectuating the deposition of the IC into or removal from the IC pocket 119. Upon the latch releasing mechanism 125 being moved out of engagement with the latches 123, the latches will snap back to their normal positions where the deposited IC is held in place against dislodgement by the top end pawls of the latches 123.
The IC carrier 116 holds an IC device in place with its leads or pins 118 exposed downwardly as shown in FIG. 10. The tester head 104 is provided with an IC socket (not shown) having contacts 104A extending from the top surface thereof. The exposed pins 118 of the IC device are pushed against the contacts 104A of the IC socket to establish electrical connection between the IC device and the socket. To this end, a pusher 120 for pushing and holding an IC device down is mounted above the tester head 104 and is configured to push the IC device accommodated in an IC carrier 116 from above into contact with the IC socket of the tester head 104.
The number of IC devices which may be connected with the tester head 104 at a time depends on the number of IC sockets mounted on the tester head 104. By way of example, where sixty-four IC devices are carried in an array of 4 rows (horizontal lines).times.16 columns (vertical lines) on a test tray TST as shown in FIG. 11, 4.times.4, that is, 16 IC sockets are arranged and mounted on the tester head 104 such that the IC devices (shown as cross-hatched) in every fourth column in each of the rows may be tested all at once. More specifically, in the first testing run the examination is conducted on sixteen IC devices located in the first, fifth, ninth and thirteenth columns in each row, the second testing run is effected on another sixteen IC devices located in the second, sixth, tenth and fourteenth columns in each row by shifting the test tray TST by a distance corresponding to one column of IC devices, and the third and fourth testing runs are carried out in the similar manner until all of the IC devices are tested. The test results are stored in a memory with the addresses determined by the serial numbers (serial numbers in one lot) assigned to the ICs, the identification number affixed to the test tray TST and the numbers assigned to the IC pockets in the test tray. It is to be appreciated that where thirty-two IC sockets may be mounted on the tester head 104, only two testing runs are required to examine all sixty-four ICs arranged in an array of 4 rows.times.16 columns.
It is also to be noted that there is another type of IC handler in which ICs to be tested are transferred from the test tray into a socket of the tester head for the test and upon the test being completed the ICs are transferred from the socket back onto the test tray for delivery, in the test chamber 102.
The IC storage section 200 comprises an IC (DUT) storage rack (or stocker) 201 for accommodating universal trays KST loaded with ICs being tested and a tested IC storage rack (or stocker) 202 for accommodating universal trays KST loaded with tested ICs sorted out by categories on the basis of the test results. The IC storage rack 201 and tested IC storage rack 202 are configured to accommodate universal trays in the form of a stack. The universal trays KST with ICs under test carried thereon stored in the form of a stack in the IC storage rack 201 are transported successively from the top of the stack to the loader section 300 where the ICs being tested are transferred from the universal trays KST onto a test tray TST on standby in the loader section 300.
The IC storage rack 201 and the tested IC storage rack 202, one of which is shown in FIG. 12, may be of identical construction and comprise a tray supporting frame 203 open at the top and having an opening at the bottom, and an elevator 204 disposed below the frame 203 so as to be vertically movable through the bottom opening. In the tray supporting frame 203 there are stored and supported a plurality of universal trays KST stacked one on another which are vertically moved by the elevator 204 acting through the bottom opening of the frame 203.
In the example illustrated in FIGS. 6 and 7, eight racks STK-1, STK-2, . . . , STK-8 are provided as tested IC storage racks 202 so as to be able to store tested ICs which may be sorted out into eight categories at a maximum according to the test results. This is because in some applications tested ICs may not only be classified into categories of "pass article" and "failure article" but also be subclassified into those having high, medium and low operation speeds among the "pass" articles and those required to be re-tested among the "failure" articles, and others. Even if the number of classifiable categories is up to eight, the unloader section 400 in the illustrated example is capable of accommodating only four universal trays KST. For this reason, if there occur some among the tested ICs which should be classified into a category other than categories assigned to the four universal trays KST arranged in the unloader section 400, the procedures taken are to return one of the universal trays KST from the unloader section 400 to the tested IC storage section 200 and in replacement transfer a universal tray KST for storing the ICs belonging to the new additional category from the tested IC storage section 200 to the unloader section 400 where those ICs are stored in the new tray.
Referring to FIG. 7, a tray transfer means 205 is disposed above the IC storage rack 201 and the tested IC storage racks 202 for movement over the entire extent of the storage racks 201 and 202 in the direction of arrangement of the racks (in the right to left direction of the testing apparatus) relative to the base plate 105.
FIG. 13 illustrates one example of the positional relation between the tray supporting frame 203 of the IC storage rack 201, the elevator 204 and the tray transfer means 205. The tray transfer means 205 is provided on its bottom with grasp means in the form of pivotable pawls 205A for grasping a universal tray KST. The tray transfer means 205 is moved to a position over the IC storage rack 201 whereupon the elevator 204 is actuated to lift the universal trays KST stacked in the IC storage rack 201, so that the uppermost universal tray KST may be engaged and grasped by the pivotable pawls 205A of the tray transfer means 205. (Each universal tray KST is formed in its sides with cutouts for receiving the pivotable pawls 205A.)
Once the uppermost universal tray KST loaded with ICs being tested has been transferred to the tray transfer means 205, the elevator 204 is lowered to its original position. The tray transfer means 205 is then horizontally moved along guide means 210 to and stopped at a predetermined position in the loader section 300 by means of power transmission means such as chains or wires where the tray transfer means 205 has its pivotable pawls 205A release the universal tray KST to allow it to drop into an immediately underlying tray receiver 207. The tray transfer means 205 having the universal tray KST unloaded therefrom is moved out of the loader section 300 again by the power transmission means.
Then, the elevator 204 is moved upward from below the tray receiver 27 having the universal tray KST placed thereon to lift up the universal tray KST loaded with ICs to be tested so that the universal tray KST is held with its upper surface facing a window 106 formed in the base plate 105 (with the upper surface of the universal tray KST exposed through the window). More specifically, pivotable pawls 208 for grasping a universal tray KST are mounted on the undersurface of the base plate 105 around the window 106, so that the universal tray KST is held in the aforesaid condition by the pivotable pawls 208 engaging in the cutouts of the universal trays KST loaded with ICs to be tested. In this condition, the ICs to be tested are loaded from the universal tray KST through the window 106 onto the test tray TST.
The base plate 105 is also formed in the area overlying the unloader section 400 with another two similar windows 106. In this example, each of the windows 106 is sized to allow the upper surfaces of two juxtaposed universal trays to face the window. Hence, the arrangement is such that tested ICs may be stored through the two windows 106 of the unloader section 400 into four empty universal trays.
As shown in FIG., 13, pivotable pawls 208 for grasping a universal tray KST are also mounted on the undersurface of the base plate 105 around the windows 106 of the unloader section 400, so that universal trays KST may be grasped by the pivotable pawls 208. Tested ICs are sorted and stored in these empty universal trays KST according to the categories assigned to respective trays.
Although not shown in FIG., 13, as with the loader section 300, the unloader section 400 is also provided with tray receivers and associated elevators 204 for temporarily keeping (supporting thereon) universal trays KST. Once one universal tray KST has been fully filled, the elevator 204 is moved up to support the tray whereupon the tray is released from the engagement with the pivotable pawls 208. Then, as the elevator 204 is moved down, the universal tray KST is lowered from the level below the window 116 to be temporarily placed on the tray receiver, and is subsequently stored in the tray storage position assigned to that particular tray by the tray transfer means 205.
Indicated by the numeral 206 in FIGS. 6 and 7 is an empty tray storage rack (or stocker) for accommodating empty universal trays KST. From this empty tray storage rack 206, empty universal trays are transported to the respective windows 106 by the tray transfer means 205 and held thereat by the associated elevators 204 to be ready for receiving tested ICs.
As discussed above with reference to FIG. 12, it has been heretofore a common practice to manually store universal trays KST from above the tray supporting frame 203 down into the IC storage rack 201 and to automatically take out universal trays KST out of the IC storage rack 201 from above the tray supporting frame 203 and transport them to the loader section 300 by the use of the transport mechanism of the handler.
In contrast, a tendency is seen lately to employ a tray storage container KAS as shown in FIG. 14 which is open only at the lower end (bottom) thereof with movable L-shaped hooks FK mounted on a pair of opposed end edges of the container. Specifically, the vertical legs of the movable L-shaped hooks FK are pivotally mounted on the opposed end edges of the container such that the horizontal legs of the respective hooks may extend into the open end of the tray storage container KAS.
With this construction, the movable hooks FK may be pivoted open outwardly to completely open the open end of the tray storage container KAS to permit a predetermined number of universal trays KST to be stored in the tray storage container KAS, whereafter upon the movable hooks FK being returned to their original positions, these universal trays KST are stored in a vertical stack within the tray storage container KAS as the lowermost universal tray KST of the stack is supported on its bottom surface adjacent the opposed end edges thereof by the movable hooks FK. Attached to the top of the tray storage container KAS is a handle HD which may be used to carry the tray storage container KAS.
The use of the tray storage container KAS constructed as described above makes it possible to store a predetermined number of universal trays KST in the tray storage container KAS at a time without resort to manual operation if the tray storage container KAS with its movable hooks FK pivoted open outwardly is lowered from above to enclose a vertical stack of universal trays KST (each loaded with ICs) followed by returning the movable hooks FK to their original positions to engage with the bottom surface of the lowermost universal tray KST of the stack.
If the tray storage container KAS in is condition is lifted up, the universal trays KST may be transported as they are stored in place in the form of a stack in the tray storage container KAS. When the trays are unloaded, the tray storage container KAS may be lowered down to a location where the trays are to be unloaded, and at that location the movable hooks FK are pivoted open outwardly to completely open the open end of the tray storage container KAS so that the container may be removed (lifted up) to leave the vertically stacked trays at that location. In this manner the universal trays may be unloaded at a desired location at a time without resort to manual operation.
It will thus be appreciated that in addition to transporting trays, whether empty or loaded with ICs, in a safe manner, the use of the tray storage container KAS constructed as described above provides the advantage of providing for loading and unloading of trays at a time without resort to manual operation, thereby greatly facilitating the operations of loading and unloading trays.
However, the tray storage container KAS as illustrated in FIG. 14 has the disadvantage that it cannot be directly installed in the conventional IC testing apparatus (specifically the handler) as described above with reference to FIGS. 6-12, since such tray storage container is configured to store and take out trays through the bottom side.